Simon Cowell joked that Lord Andrew Lloyd Webber should hire an 'X Factor' contestant to replace Nicole Scherzinger in 'Cats'.

Simon Cowell

Simon Cowell

The music mogul, 56, made the dig at the 68-year-old composer - who was "furious" when Nicole dropped out of his West End show to reprise her role as a judge - after 23-year-old KM from Thailand sang the pop star's favourite song 'Memory' from the musical in tonight's (28.08.16) episode.

Nicole joined in with KM as he struggled to hit the notes of the ballad and after the duet Simon gave his verdict, saying: "Look, I think it probably didn't go exactly where you thought it was going to go, but I like you. But this is not for you, so it is a no today. Don't feel too bad, how many people get to sing 'Memory' with this one."

Pointing at Nicole, he teasingly added: "Showed you up. If I was Andrew Lloyd Webber, this one out, that one in."

But Simon couldn't resist looking straight into the camera and giving viewers at home a cheeky wink, and saying "That's for you, Andrew."

Louis Walsh and Sharon Osbourne cracked up but Nicole was notably embarrassed and covered her mouth before she exploded into a fit of giggles.

Simon's joke follows Andrew publicly slamming the brunette beauty for ditching her role as Grizabella in 'Cats' just a week before it was due to go on Broadway.

Elsewhere in 'The X Factor,' 39-year-old Rebecca Ryan got four yeses after she wowed the judges with a moving rendition of Sarah McLachlan's 1997 hit 'In The Arms of An Angel'.

The single mum from Tanworth in Warwickshire had a record deal aged 17 but was dropped from her label and is looking forward to second chance at chart success.